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Viewing 1 to 30 of 9988
Technical Paper
2014-09-16
Zachary A. Collier, Steve Walters, Dan DiMase, Jeffrey M. Keisler, Igor Linkov
Counterfeit electronic components entering into critical infrastructure and applications through the global supply chain threaten the economy and national security. In response to the growing threat from counterfeits, the Society of Automotive Engineers G-19 Committee is developing AS6171. This aerospace standard is focused on testing facilities with a goal of standardizing the process of counterfeit detection. An integral part of the standard is a semi-quantitative risk assessment method. This method assigns risk scores to electronic components based on a number of relevant criteria, and places the components into one of five risk tier levels corresponding to an appropriate level of laboratory testing to ensure the authenticity of the component. In this way, the methodology aims at standardizing the risk assessment process and bases the identified risk as guidance for commensurate testing protocols. This paper outlines the risk assessment method contained within AS6171 and briefly explores other complementary efforts and research gaps within the G-19 and electronics community.
Technical Paper
2014-04-01
Vijay Somandepalli, Hubert Biteau
The emergence of Plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs) as a viable means of transportation has been coincident with the development of lithium-ion (Li-ion) battery technology and electronics. These developments have enabled the storage and use of large amounts of energy that were previously only possible with internal combustion engines. However, the safety aspects of using these large energy storage battery packs are a significant challenge to address. In addition, the rapid advances in electrode and electrolyte materials for Li-Ion batteries have made comparisons and ranking of safety parameters difficult because of the substantial variations in cell designs. In this work, we outline a method for quantifying the thermal safety aspects of Li-ion battery technologies using a Cone Calorimeter. The Cone Calorimeter is a suitable tool to measure and quantify critical information such as the heat release rate and total energy released from the combustion of organic material.
Technical Paper
2014-04-01
Vijay Somandepalli, Kevin Marr, Quinn Horn
As lithium-ion cells and systems become larger and more ubiquitous in automotive applications, fire and explosion hazards that are rare or non-existent in smaller systems may exist in these larger systems. One potential hazard can occur when flammable gases emitted from a lithium-ion cell failure accumulate in or around automobiles and are ignited by electrical activity or by the cells themselves and result in a fire or explosion. In some instances, the safety aspects related to fires and explosions protection of electric vehicles and hybrid vehicles using these large energy storage battery packs are a significant challenge to address. This paper describes and characterizes the combustion and explosion hazards that can occur when a lithium ion battery pack fails and goes into thermal runaway in an enclosed space. Metrics such as gas composition, maximum overpressure, rate of pressure rise, and flammability limits are described. This information can be helpful to battery and pack designers, vehicle designers, first responders and emergency personnel in developing strategies to mitigate and prevent explosion hazards from the use of battery packs in automobiles and other fields where large battery packs are used.
Technical Paper
2014-04-01
Parul Goyal, Feng Liang, Olof Oberg
Abstract The aim of the paper is to describe how Volvo Construction Equipment uses a virtual product development process to analyze potential risks, find root causes and optimize future product development. A model based method is used to analyze a potential risk in the design of Wheel Loader transmissions. The risk was recognized from failure mode and effect analysis (FMEA), and a simulation model using AMESim modeling tool was developed to analyze the behavior of the new design. Together with test rig result, it is proved that the model based method gives a considerably accurate prediction of the system behavior. By using the model based approach, lead time for development process is reduced and important feedbacks from simulation model are obtained on early stage of the development. This paper further presents the use of the simulation model as a tool to predict the potential risks in the extreme operating conditions, which are difficult to test on the vehicle test bench.
Technical Paper
2014-04-01
Qiang Yi, Stanley Chien, David Good, Yaobin Chen, Rini Sherony
Abstract According to pedestrian crash data from 2010-2011 the U.S. General Estimates System (GES) and the Fatality Analysis Report System (FARS), more than 39% of pedestrian crash cases occurred at night and poor lighting conditions. The percentage of pedestrian fatalities in night conditions is over 77%. Therefore, evaluating the performance of pedestrian pre-collision systems (PCS) at night is an essential part of the pedestrian PCS performance evaluation. The Transportation Active Safety Institute (TASI) of Indiana University-Purdue University Indianapolis (IUPUI) is conducting research for the establishment of PCS test scenarios and procedures in collaboration with Toyota's Collaborative Safety Research Center. The objective of this paper is to describe the design and implementation of a reconfigurable road lighting system to support the pedestrian PCS performance evaluation for night road lighting conditions. First, the test conditions of the road lighting (light intensity and uniformity) are generated by combining recommendations from road lighting design standards and the average measured lighting levels at various crash locations.
Technical Paper
2014-04-01
Hang Yin, Weiming Zeng, Guobiao Yang, Songgang Li
Abstract When an object was subjected an impact loading, stress wave was produced in the object. Studying the regularity of stress-wave propagation was significant to the study of objects subjected to impact loading. When stress wave travelled in the object, principal stress on free boundary was useful to theoretical analysis and calculation. In this article, a new kind of dynamic photoelastic apparatus was used. Isochromatic and isoclinic of the object subjected to impact loading could be obtained combining dynamic photoelastic experiment and related test equipment. By analyzing the isoclinic, there would be a conclusion that the angle between the isoclinic and the free boundary was not 0°or 90°. So the values of the two principal stress on the boundary were all not 0. The result obtained from the electrometric method came to the same conclusion. Analysis showed the result of dynamic photoelastic method was compatible with the result of electrometric method. So the method in this article was feasible and accurate.
Technical Paper
2014-04-01
Haizhen Liu, Weiwen Deng, Changfu Zong, Jian Wu
Abstract This paper first presents an algorithm to detect tire blowout based on wheel speed sensor signals, which either reduces the cost for a TPMS or provides a backup in case it fails, and a tire blowout model considering different tire pressure is also built based on the UniTire model. The vehicle dynamic model uses commercial software CarSim. After detecting tire blowout, the active braking control, based on a 2DOF reference model, determines an optimal correcting yaw moment and the braking forces that slow down and stop the vehicle, based on a linear quadratic regulator. Then the braking force commands are further translated into target pressure command for each wheel cylinder to ensure the target braking forces are generated. Some simulations are conducted to verify the active control strategy. From the simulation results, it is shown that this active brake control strategy can not only ensure the flat tire vehicle stability, but also slow down the vehicle with a safe speed and for a shorter distance.
Technical Paper
2014-04-01
Erdem Uzunsoy, Emmanuel Bolarinwa, Oluremi Olatunbosun, Rui He
Abstract Sloped medians provide a run-off area for errant vehicles so that they can be safely stopped off-road with or without barriers placed in the sloped median. However, in order to optimize the design of sloped medians and the containment barriers, it is essential to accurately model the behavior of vehicles on such sloped terrain surfaces. In this study, models of a vehicle fleet comprising a small sedan and a pickup truck and sloped terrain surface are developed in CarSim™ to simulate errant vehicle behavior on sloped median. Full-scale crash tests were conducted using the vehicle fleet driven across a 9.754 meters wide median with a 6:1 slope at speeds ranging from 30 to 70 km/h. Measured data such as the lateral accelerations of the vehicle as well as chassis rotations (roll and pitch) were synchronized with the vehicle motion obtained from the video data. The measured responses were compared with responses obtained from simulation in CarSim™ to validate the vehicle and slope terrain models.
Technical Paper
2014-04-01
Shweta Rawat, Soumya Kanta Das
Abstract With the ever increasing emphasis on vehicle occupant safety, the safety of pedestrians is getting obscured behind the A-pillars that are expanding in order to meet the federal roof crush standards. The serious issue of pillar blind spots poses threats to the pedestrians who easily disappear from driver's field of view. To recognize this blinding danger and design the car around the driver's eye, this paper proposes the implementation of Aluminum Oxynitride marked under name AlON by Surmet Corporation for fabrication of A-pillars that can allow more than 80% visibility through them. AlON is a polycrystalline ceramic with cubic spinel crystal structure and is composed of aluminum, oxygen and nitrogen. With hardness more than 85% than sapphire, its applications range from aerospace to defense purposes which qualify it in terms of strength and thus imply that it can be conveniently used as A-pillars in vehicles. Furthermore, it possesses characteristics of being bonded to metals as well.
Technical Paper
2014-04-01
Jeong Keun Lee, Byung-Jae Ahn, Ye Ri Hong
Abstract In current inflatable curtain airbag development process, the curtain airbag performance is developed sequentially for the airbag coverage, FMVSS 226, FMVSS 214 and NCAP. Because the FMVSS 226 for the ejection mitigation and the NCAP side impact test require the opposite characteristics in terms of the dynamic stiffness of the inflatable curtain airbag, the sequential development process cannot avoid the iteration for dynamic stiffness optimization. Airbag internal pressure characteristics are can be used to evaluate the airbag performance in early stage of the development process, but they cannot predict dynamic energy absorption capability. In order to meet the opposite requirements for both FMVSS 226 and NCAP side impact test, a test and CAE simulation method for the inflatable curtain airbag was developed. The purpose of this study is to standardize the test setup for comparing the energy absorption capability of inflatable curtain airbag and to make criteria for meeting both FMVSS 226 and NCAP early in the program.
Technical Paper
2014-04-01
Youmei Zhao
The Hybrid III 50th male dummy is widely used in front impact crash tests in the world to evaluate the vehicle safety performance. The chest impact calibration test should be conducted after certain amount of crash tests to ensure that the dummy has the right performance during the crash tests. The impact velocity in the current chest calibration tests is 6.71 m/s and the chest displacement corridor is 63.5 mm to 72.6 mm, which was based on the cadaver tests carried out in 1970s. After over forty years' development, the vehicle safety has been improved significantly with applications of seat belt and airbag technologies. In the European and China new car assessment program (ENCAP and CNCAP), the higher performance limit for the front impact dummy chest compression is 22mm and the lower performance limit is 50 mm, which is much lower than the dummy chest calibration corridor. In this paper, the dummy rib assembly structure is analyzed and the rib impact FEA simulation was also conducted.
Technical Paper
2014-04-01
Sanjeev Kumar, Deepak Katyal, Amit Singh
Abstract Recent advancement in numerical solutions and advanced computational power has given a new dimension to the design and development of new products. The current paper focuses on the details of work done in order to improve the vehicle performance in Offset deformable Barrier (ODB) crash as per ECER-94. A Hybrid approach involving the Structural Crash CAE as well as Multi-body Simulation in MADYMO has been adopted. In first phase of the development, CAE results of Structural deformation as well as Occupant injury of the baseline model were correlated with physical test data. The second phase includes the improvement in intrusion and crash energy absorption by structural countermeasures in the vehicle body. In third phase parametric study has been carried out via Madymo simulation in order to decide on the factors which can be controlled in order to mitigate the Occupant injury. Recommendations of Madymo simulation have been confirmed by conducting Physical sled tests. Finally a cost and weight effective countermeasure package which involves the modification in Body structure and Restraint system has been developed in order to comply with the ECE R-94 offset crash regulation.
Technical Paper
2014-04-01
Venkat Pisipati, Srikanth Krishnaraj, Edgar Quinto Campos
Abstract Motor vehicle safety standards are getting to be more demanding with time. For automotive interiors, instrument panel (IP) head impact protection is a key requirement of the Federal Motor Vehicle Safety Standard (FMVSS) 201. To ensure compliance of this requirement, head impact tests are conducted at 12 and 15 mph for performance verification. Computer simulation has become more prevalent as the primary development tool due to the significant reduction in time and cost that it offers. LS-DYNA is one of the most commonly used non-linear solvers in the automotive industry, particularly for safety related simulations such as the head impact of automotive interiors. LS-DYNA offers a wide variety of material models, and material type 024 (MAT 024, piecewise linear plasticity) is one of the most popular ones [1]. Although it was initially developed for metals, it is commonly used for polymers as well. LS-DYNA also offers several other material models specifically developed to simulate polymers, such as material types 019, 089, 123, to name a few.
Technical Paper
2014-04-01
Alan R. Wedgewood, Patrick Granowicz, Zhenyu Zhang
Abstract Materials used in automotive components play a key role in providing crash safety to passengers and pedestrians. DuPont's lightweight hybrid material technology, which combines injection molded fiber reinforced plastics with drape molded woven composite materials, provides safety engineers with stiff energy absorbing alternatives. In an effort to validate the hybrid material's crash performance while avoiding expensive crash testing, numerical tools and methodologies are applied in evaluation of a hybrid composite test beam. Multi-scale material models capturing nonlinear strain-rate dependency, anisotropic characteristics, and failure criteria, are calibrated on a fiber reinforced plastic and a woven fabric. The fiber orientation and warp/weft angles were extracted from injection and drape molding simulation. The material laws and orientation information are coupled in a single finite element analysis to predict the performance of the hybrid composite beam under a dynamic three point bending load.
Technical Paper
2014-04-01
Sangzhi Zhu, Haiping Du, Nong Zhang, Lifu Wang
In this paper, a more sophisticated mathematical linear model for a roll-plane active hydraulically interconnected suspension (HIS) system was developed. Model parameters tuning were then carried out, which resulted in a model that is capable of producing rather accurate estimation of the system, with significant improvements over models built previously. For the verification of the new model, two simulations and corresponding experiments are conducted. Data comparisons between the simulations and experiments show high consistent responses of the model and the real system, which validated the robustness and accuracy of the new mathematical model. In this process, the characteristics of the pressure response and the rise time inside the actuators have been revealed due to the presence of the flow.
Technical Paper
2014-04-01
Chi-Chun Yao, Jin-Yan Hsu, Yu-Sheng Liao, Ming Hung Li
Abstract Vehicle Rollover Prevention/Warning Systems have recently been an important topic in Advanced Driver Assistance Systems (ADAS) of automotive electronics field. This paper will propose a rollover-prevention system implementation with vehicle dynamic model, video-detection technique and rollover index to help the driver avoid accidents as driving into a curve. Due to the reason that vehicle rollover motion analysis needs complicated computation and accurate parameters of vehicle stability in real time, in the first stage a vehicle dynamic model based on Extended Kalman Filter (EKF) algorithm is built, which can estimate vehicle roll/yaw motion in the curve by vehicle sensors. And then the image-based technique will be employed in detecting the front road curvature, and combined in the system to predict vehicle steering status. The final stage is to apply the vehicle rollover index with estimated vehicle motion to predict the dangerous level to drivers for warning. In the system validation, a Digital Signal Processor (DSP) with Microcontroller Unit (MCU) hardware structure is equipped and implemented in our vehicle experimental platform.
Technical Paper
2014-04-01
Masayuki Takemura, Masato Imai, Masahiro Kiyohara, Kota Irie, Masao Sakata, Shoji Muramatsu
Abstract Driver safety continues to be improved by advances in active safety technologies. One important example is Lane Departure Warning (LDW). European regulators soon will require LDW in big cars to reduce traffic accidents and New Car Assessment Programs in various countries will include LDW in a few years. Our focus is on rear cameras as sensing devices to recognize lane markers. Rear cameras are the most prevalent cameras for outside monitoring, and new Kids and Cars legislation will make them obligatory in the United States from 2014. As an affordable sensing system, we envision a rear camera which will function both as a rear-view monitoring device for drivers and as an LDW sensing device. However, there is a great difficulty involved in using the rear camera: water-droplets and dirt are directly attached to the lens surface, creating bad lens condition. The purpose of this study is to improve the durability of lane recognition systems when water-droplets and dirt are deposited on the lens surface.
Technical Paper
2014-04-01
Gauri Ranadive, Anindya Deb, Bisheshwar Haorongbam
Abstract Load cells and accelerometers are commonly used sensors for capturing impact responses. The basic objective of the present study is to assess the accuracy of responses recorded by the said transducers when these are mounted on a moving impactor. In the present work, evaluation of the responses obtained from a drop-weight impact testing set-up for an axially loaded specimen has been carried out with the aid of an equivalent lumped parameter model (LPM) of the set-up. In this idealization, a test component such as a steel double hat section subjected to axial impact load is represented with a nonlinear spring. Both the load cell and the accelerometer are represented with linear springs, while the impactor comprising a hammer and a main body with the load cell in between are modelled as rigid masses. An experimentally obtained force-displacement response is assumed to be a true behavior of a specimen. By specifying an impact velocity to the impactor as an initial condition and using an implicit time integration technique, it is shown that the model accurately reproduces the input load-displacement behavior of the nonlinear spring corresponding to the tested component.
Technical Paper
2014-04-01
Thang Nguyen, Stuart Wooters
As software (SW) becomes more and more an important aspect of embedded system development, project schedules are requiring the earlier development of software simultaneously with hardware (HW). In addition, verification has increasingly challenged the design of complex mixed-signal SoC products. This is exacerbated for automotive safety critical SoC products with a high number of analogue interfaces (sensors and actuators) to the physical components such as an airbag SoC chipset. Generally, it is widely accepted that verification accounts for around 70% of the total SoC development. Since integration of HW and SW is the most crucial step in embedded system development, the sooner it is done, the sooner verification can begin. As such, any approaches which could allow verification and integration of HW/SW to be deployed earlier in the development process and help to decrease verification effort, (e.g.: accelerate verification runs) are of extreme interest. In the described context, this paper addresses not only the design and verification challenges of such embedded systems but also proposes a new development, verification and validation workflow using an FPGA-based SoC Emulation System with synthesizable analogue functional stubs and a risk minimizing analogue test chip, which emulates and partially implements respective mixed-signal behavior of the ASIC SoC hardware.
Technical Paper
2014-04-01
Prasad Rao Yerraguntla, Shashi Kulkarni, Deepak Asthana
Abstract Automotive Audio Signaling system is very vital and is controlled by local regulatory requirements. In India, usage of horn is very frequent due to highly congested traffic conditions, and is in the order of 10 to 12 times per kilometer. This results in the deterioration of the “contact”, which enables the functioning of the device. Hence the device requires premature replacement or frequent tuning, which are time consuming and results an increase in warranty costs and cost of service as well. Thus, to overcome this problem a unique and novel approach is proposed in this paper which enhances the life of the automobile horn, by implementing an additional pair of Contacts on circuit breakers, providing a parallel path for the power supply. This effort ensures that the life of the horn is increased by 5 times than the existing design. In addition, this approach completely eliminates the problems of premature failure or frequent tuning, yet without any change in the physical dimensions of the device, thus ensuring that no additional engineering efforts are required for its implementation.
Technical Paper
2014-04-01
Sanjeev Kumar, Rahul Bettakote, Pinak Deb
Abstract Offset crash compliance of a compact car is severe due to the compact layout and stringent fuel economy, weight and cost targets. Scope of the current work is to improve the structural crash performance of a compact car through CAE, in order to meet the offset frontal crash requirements as per ECE R94 Regulation. The project has been classified in three main phases. First phase includes the evaluation of baseline vehicle in CAE. In order to ensure the accuracy of CAE prediction, a methodology for predicting Spotweld rupture was implemented. Using this methodology, it is possible to find out the location and time of spotweld rupture as well as propagation of spotweld rupture in CAE. CAE results of spotweld rupture prediction showed good agreement with the physical test. In second phase, design iterations were carried out in order to meet the performance targets of structural deformation. At critical locations of spotweld rupture, spotwelds were reinforced by addition of arc welds tugs and bolts.
Technical Paper
2014-04-01
Payman Khani, Mehrdad S. Sharbaf
Abstract Vehicular Network is an emerging and developing technology to improve traffic management and safety issues, and enable a wide range of value-added services such as collision warning/avoidance. Many applications have been designed to provide safety and comfort for passengers. This technology is a prolific area for attackers who will attempt to challenge the network with their malicious or rational attacks. In this paper we elaborate what a vehicular network is, different kinds of communication in this field, main mechanism and related parts and how vehicular networks work then we introduce some of its applications. After primary familiarity with this system we investigate to different type of attacker, more important security issues, How to secure vehicular networks (security requirements and some tools and methods to achieve secure vehicular networks), difficulties and providing viable security solutions, and at the end briefly explanation of related standards.
Technical Paper
2014-04-01
Armin Wasicek
Intellectual property rights and their protection is a cornerstone of the automotive value chain. The automotive industry is composed by a meshwork of tightly integrated organizations that cooperate and compete in a hierarchical marketplace. Trading know-how and other virtual assets between participants is an essential part of this business. Thereby, software as a medium to transport ideas, innovations, and technologies plays a particular role. Protection of virtual goods and their associated rights is a current issue whose solution will determine how business will be done in the future automotive market. Automotive experts and researchers agree that ICT security technologies are a vital part to implement such a market. In this paper we examine the software life cycle of an automotive Electronic Control Unit (ECU) and discuss potential threats and countermeasures for each stage. In particular, we will look at the following threats: (1) development (leakage of know-how through insiders or industrial espionage), (2) production (leakage through split inventor/producer companies, (3) deployment and service (manipulation of ECUs), and (4) aftersales (combating counterfeit ECUs and spare parts).
Technical Paper
2014-04-01
Satoshi Otsuka, Tasuku Ishigooka, Yukihiko Oishi, Kazuyoshi Sasazawa
Abstract In-vehicle networks are generally used for computerized control and connecting information technology devices in cars. However, increasing connectivity also increases security risks. “Spoofing attacks”, in which an adversary infiltrates the controller area network (CAN) with malicious data and makes the car behave abnormally, have been reported. Therefore, countermeasures against this type of attack are needed. Modifying legacy electronic control units (ECUs) will affect development costs and reliability because in-vehicle networks have already been developed for most vehicles. Current countermeasures, such as authentication, require modification of legacy ECUs. On the other hand, anomaly detection methods may result in misdetection due to the difficulty in setting an appropriate threshold. Evaluating a reception cycle of data can be used to simply detect spoofing attacks. However, this may result in false detection due to fluctuation in the data reception cycle in the CAN. We propose the “delayed-decision cycle detection” method for improving a conventional cycle detection method, which does not require modification of legacy ECUs, detects intrusions with a low misdetection rate, and prevents intrusions.
Technical Paper
2014-04-01
Dawid Trawczynski, Janusz Zalewski, Janusz Sosnowski
In the paper we discuss how a single node communication interface failure in a time-triggered system can be used to model a DoS-type attack. More so, we present a design approach based on active detection of common DoS characteristics, which can serve as a template for attack detection. This approach is feasible in time-triggered systems because of the periodic and deterministic characteristics either at the fieldbus communication or application level. We support our discussion with an example case study of a vehicle braking system implementing time-triggered messages disturbed by fault injection.
Technical Paper
2014-04-01
Yohsuke Tamura, Masayuki Takeuchi, Kiyotaka Maeda, Noriaki Ohtsuka, Kenji Sato
The localized fire test provided in the Global Technical Regulation for Hydrogen Fuel Cell Vehicles gives two separate test methods: the ‘generic installation test - Method 1′ and the ‘specific vehicle installation test - Method 2′. Vehicle manufacturers are required to apply either of the two methods. Focused on Method 2, the present study was conducted to determine the characteristics and validity of Method 2. Test results under identical burner flame temperature conditions and the effects of cylinder protection covers made of different materials were compared between Method 1 and Method 2. The following results were obtained: (1) Methods 1 and 2 produced nearly identical results when the minimum temperature profile in the GTR test procedure was followed in both cases. (2) A steel protection cover on the cylinder significantly lowered cylinder surface temperatures during the fire test until activation of the thermal pressure relief device (TPRD). (3) A thermoplastic cover on the cylinder melted during the fire test and produced an engulfing pool fire during the localized fire portion of the test that accelerated activation of the TPRD.
Technical Paper
2014-04-01
Raúl Ochoterena, Maria Hjohlman, Michael Försth
Abstract Fires in the engine compartments of surface and underground non-rail heavy duty vehicles are still highly frequent. Statistics show that most of the reported fires commenced in the engine compartment and that these were not promptly detected by the drivers. Fires which were not detected rapidly, spread oftentimes beyond the firewall of the engine compartment having notorious economical and environmental repercussions; furthermore, endangering the safety of the occupants. Detecting fires in the engine compartments of heavy duty (HD) vehicles with inexpensive and simple automatic detection systems is in general challenging. High air flows and large amounts of suspended pollutants, together with the complicated geometry and wide range of surface temperatures typically occurring during the normal operation of the vehicle, complicate the reliable operation of almost all types of detectors. This work presents a theoretical study assessing the effectiveness of different detection systems in a simulated fire scenario.
Technical Paper
2014-04-01
Jeff D. Colwell
Abstract Results from a full-scale vehicle burn test involving a 1998 compact passenger car were used to evaluate vehicle fire dynamics and how burn patterns produced during the fire correlated with important characteristics of the fire, such as the area of origin. After the fire was initiated at the air filter in the engine compartment, the fire spread locally and, once the temperature near the origin reached about 750°C, the temperature at all but one location within the engine compartment began to increase. These temperatures continued to increase for the next 6 minutes and then a temperature gradient began to develop in the passenger compartment between the ceiling and the floor. About 5 minutes after the engine compartment became fully involved, the ceiling temperature reached about 590°C and flame spread within the passenger compartment increased. Over the next 4 minutes, the passenger compartment also became fully involved. The fire then spread to the trunk and the rear wheels before self-extinguishing.
Technical Paper
2014-04-01
Guanyu Zheng, Indrek Wichman, Andre Benard, Hongyu Wang, Xiaohui Li, Jie Gao
Abstract Flame spread over a melting thermally thick composite polymer is investigated in a channel flow above a condensed fuel. The condensed fuel consists of an isotropic (melted layer of) liquid near the heated surface and an anisotropic (not-yet-melted) solid surrounding it. The influence of the solid anisotropy is evaluated by changing the solid conductivity (ksx or ksy) in one particular direction (x in horizontal flame spread direction or y in vertical direction, see schematics in Figure 1) while keeping the other properties fixed. Note that the liquid conductivity kl has no isotropic behavior. Numerically, it is found that the flame spread rate decreases with either increasing ksx or ksy. The decrease with respect to ksy is less than for a comparable case described by the de Ris formula for an isotropic pure solid. The flame spread rate is more accurately determined by an analytical formula derived for spread across a melting solid fuel. Qualitatively, the liquid layer extent decreases with either increasing ksx or ksy due to the role played by the solid conduction as a heat loss mechanism in a thermally thick fuel.
Technical Paper
2014-04-01
Pit Schwanitz, Sebastian Werner, Johannes Zerbe, Dietmar Göhlich
Abstract A new methodology for crash sensitive vehicle structures has been developed to be used during the early stage of the Product Development Process (PDP). By frontloading significant and simplified CAE simulations and the use of stochastic optimization methods in conjunction with highly parametric CAD models, new concepts can be quickly identified and evaluated based on reliable product insight. Vehicle crashboxes have been chosen for verification of the methodology. An analysis of different but comparable vehicles showed a large variety of designs although they all absorb the energy of low speed crashes within a velocity of up to 15km/h. A powerful optimization model with a parametric geometry engine, a crash-solver and suitable optimization software, used within a batch process, has been established. The optimal results for one particular crashbox concept are presented to demonstrate the methodology and the benefit of the approach. Due to the relocation of the variant calculation at early stage, the optimization potential can be used extensively.
Viewing 1 to 30 of 9988